Healthcare-associated infections (HAIs) cause significant morbidity and mortality in pediatric inpatients. Significantly less is known about thes HAIs among children in ambulatory settings, including incidence rates, risk-factors, outcomes and costs. Pediatric ambulatory central line-associated blood stream infections (CLABSI) and catheter-associated urinary tract infections (CAUTI), and surgical site infections (SSI) following ambulatory surgery, likely harm thousands of children annually, although precise epidemiologic data are unknown. Single-center studies and disease-specific studies led by this proposal's principal investigator, suggest the burden of ambulatory pediatric HAIs may be 3 times higher than inpatient pediatric HAIs. In addition, existing ambulatory HAI studies often utilize labor intensive surveillance and data collection methods, making ongoing identification of HAIs challenging and interventions to reduce these infections difficult to scale and disseminate. This grant proposes a multisite, epidemiologic investigation into 3 pediatric ambulatory HAIs using the New York City Clinical Data Research Network (NYC-CDRN). The NYC- CDRN is a comprehensive and longitudinal healthcare data repository from 5 pediatric healthcare systems in a diverse region. This proposal directly responds to the Agency for Healthcare Research and Quality's (AHRQ) Funding Opportunity Announcement HS-15-002 on ambulatory patient safety, focuses on an urban population, and will benefit an AHRQ priority population: children. Utilizing both clinical and administrative electronic data, and intensive chart review methodologies, we will identify incidence rates, risk factors, patient outcomes and costs for ambulatory pediatric CLABSI and CAUTI, and SSI following ambulatory surgery. Additionally, we will develop and validate Classification and Regression Tree (CART) predictive models for HAI events and central line and urinary catheter days based only on clinical and administrative electronic data. This research will draw attention to pediatric ambulatory patient safety, reduce the ambulatory HAI surveillance and data collection burden and serve as the foundation for future projects aimed at reductions of ambulatory pediatric HAIs across multiple institutions.